Acids Bases and Salts Class 10 Science Chapter 2 Extra Questions are available here. By using these extra questions, you can improve your knowledge and perform well in exams. The Extra Questions have been prepared by subject experts of CBSE Wale, aiming to make learning easier and more convenient for you.
Acids Bases and Salts Class 10 Science Chapter 2 Extra Questions
Introduction
Question 1: What causes sour and bitter tastes in food?
Answer: Acids and bases present in the food.
Question 2: What are the remedies for acidity after overeating?
Answer: Lemon juice, vinegar, or baking soda solution.
Question 3: How can you test sour and bitter substances without tasting them?
Answer: Using indicators like litmus and turmeric.
Question 4: What colour does litmus paper turn when in contact with an acid?
Answer: Red.
Question 5: What colour does litmus paper turn when in contact with a base?
Answer: Blue.
Question 6: What can soap do to curry stains on white cloth?
Answer: Change the colour from yellow to reddish-brown.
Question 7: What are some synthetic indicators used for testing acids and bases?
Answer: Methyl orange and phenolphthalein.
Question 8: What is a litmus solution?
Answer: A purple dye extracted from lichen used as an indicator.
Question 9: What colour is a litmus solution when it is neutral?
Answer: Purple.
Question 10: What are some natural indicators that can identify the presence of acids or bases?
Answer: Red cabbage leaves, turmeric, and coloured petals of China Rose flowers.
Question 11: What taste is associated with acids?
Answer: Sour.
Question 12: What taste is associated with bases?
Answer: Bitter.
Question 13: What are some examples of flowers whose coloured petals can act as indicators?
Answer: Hydrangea, Petunia, and Geranium.
Question 14: What colour change occurs in red cabbage leaves when in contact with an acid?
Answer: The colour changes to red or purple.
Question 15: What colour change occurs in red cabbage leaves when in contact with a base?
Answer: The colour changes to green or blue.
Question 16: How is turmeric used as an acid-base indicator?
Answer: Turmeric changes its colour from yellow to reddish brown in the presence of a base and remains yellow in an acid.
Acids and Bases in the Laboratory
Question 1: What is the colour change of red litmus in hydrochloric acid (HCl)?
Answer: No change.
Question 2: What is the colour change of blue litmus in hydrochloric acid (HCl)?
Answer: Turn red.
Question 3: What is the colour change of phenolphthalein in hydrochloric acid (HCl)?
Answer: No change.
Question 4: What is the colour change of methyl orange in hydrochloric acid (HCl)?
Answer: Turns red.
Question 5: What is the colour change of red litmus in sulphuric acid (H₂SO₄)?
Answer: No change.
Question 6: What is the colour change of blue litmus in sulphuric acid (H₂SO₄)?
Answer: Turn red.
Question 7: What is the colour change of phenolphthalein in sulphuric acid (H₂SO₄)?
Answer: No change.
Question 8: What is the colour change of methyl orange in sulphuric acid (H₂SO₄)?
Answer: Turns red.
Question 9: What is the colour change of red litmus in nitric acid (HNO₃)?
Answer: No change.
Question 10: What is the colour change of blue litmus in nitric acid (HNO₃)?
Answer: Turn red.
Question 11: What is the colour change of phenolphthalein in nitric acid (HNO₃)?
Answer: No change.
Question 12: What is the colour change of methyl orange in nitric acid (HNO₃)?
Answer: Turns red.
Question 13: What is the colour change of red litmus in acetic acid (CH3COOH)?
Answer: No change.
Question 14: What is the colour change of blue litmus in acetic acid (CH3COOH)?
Answer: Turns red.
Question 15: What is the colour change of phenolphthalein in acetic acid (CH3COOH)?
Answer: No change.
Question 16: What is the colour change of methyl orange in acetic acid (CH3COOH)?
Answer: Turns red.
Question 17: What is the colour change of red litmus in sodium hydroxide (NaOH)?
Answer: Turn blue.
Question 18: What is the colour change of blue litmus in sodium hydroxide (NaOH)?
Answer: No change.
Question 19: What is the colour change of phenolphthalein in sodium hydroxide (NaOH)?
Answer: Turns pink.
Question 20: What is the colour change of methyl orange in sodium hydroxide (NaOH)?
Answer: Turns yellow.
Question 21: What is the colour change of red litmus in calcium hydroxide [Ca(OH)₂]?
Answer: Turns blue.
Question 22: What is the colour change of blue litmus in calcium hydroxide [Ca(OH)₂]?
Answer: No change.
Question 23: What is the colour change of phenolphthalein in calcium hydroxide [Ca(OH)₂]?
Answer: Turns pink.
Question 24: What is the colour change of methyl orange in calcium hydroxide [Ca(OH)₂]?
Answer: Turns yellow.
Question 25: What is the colour change of red litmus in potassium hydroxide (KOH)?
Answer: Turn blue.
Question 26: What is the colour change of blue litmus in potassium hydroxide (KOH)?
Answer: No change.
Question 27: What is the colour change of phenolphthalein in potassium hydroxide (KOH)?
Answer: Turns pink.
Question 28: What is the colour change of methyl orange in potassium hydroxide (KOH)?
Answer: Turns yellow.
Question 29: What is the colour change of red litmus in magnesium hydroxide [Mg(OH)₂]?
Answer: Turns blue.
Question 30: What is the colour change of blue litmus in magnesium hydroxide [Mg(OH)₂]?
Answer: No change.
Question 31: What is the colour change of phenolphthalein in magnesium hydroxide [Mg(OH)₂]?
Answer: Turns pink.
Question 32: What is the colour change of methyl orange in magnesium hydroxide [Mg(OH)₂]?
Answer: Turns yellow.
Question 33: What is the colour change of red litmus in ammonium hydroxide (NH₄OH)?
Answer: Turn blue.
Question 34: What is the colour change of blue litmus in ammonium hydroxide (NH₄OH)?
Answer: No change.
Question 35: What is the colour change of phenolphthalein in ammonium hydroxide (NH₄OH)?
Answer: Turns pink.
Question 36: What is the colour change of methyl orange in ammonium hydroxide (NH₄OH)?
Answer: Turns yellow.
Question 37: What are olfactory indicators?
Answer: Substances that change their odour or smell in acidic or basic environments.
Question 38: Give examples of olfactory indicators.
Answer: Vanilla, onion, and clove.
Question 39: What happens to the smell of vanilla, onion, and clove when mixed with an acidic solution?
Answer: Their smell does not change.
Question 40: What happens to the smell of vanilla, onion, and clove when mixed with a basic solution?
Answer: Their smell disappears.
Question 41: Are there any specific guidelines for using olfactory indicators?
Answer: Yes, it is important to ensure proper ventilation when using them due to the potential for strong odours.
Question 42: What is the advantage of using olfactory indicators?
Answer: They provide a sensory perception of acidity or basicity beyond visual observations.
Question 43: Can the odour changes in olfactory indicators be reversed?
Answer: Yes, once the indicator is removed from the acidic or basic solution, its original smell can return.
How do Acids and Bases React with Metals?
Question 1: What is the chemical equation for the reaction between dilute sulphuric acid and zinc?
Answer: H₂SO₄ + Zn → ZnSO₄ + H₂.
Question 2: What does the metal do in the reaction between a metal and an acid?
Answer: The metal displaces hydrogen atoms from the acid.
Question 3: What is the general equation for the reaction of a metal with an acid?
Answer: Acid + Metal → Salt + Hydrogen gas.
Question 4: What are the products of the reaction between sodium hydroxide (NaOH) and zinc (Zn)?
Answer: The products are sodium zincate (Na₂ZnO₂) and hydrogen gas (H₂).
Question 5: Which metal is capable of displacing hydrogen from sulphuric acid?
Answer: Zinc (Zn) has a higher reactivity and can displace hydrogen.
Question 6: What factors determine the reactivity of metals with acids?
Answer: The reactivity of metals with acids depends on factors such as their position in the reactivity series.
Question 7: Can you give an example of a less reactive metal that may not react with acids?
Answer: Silver (Ag) is an example of a less reactive metal that may not react with acids.
Question 8: Why is hydrogen gas liberated in the reaction between metals and acids?
Answer: The displacement of hydrogen atoms from the acid results in the liberation of hydrogen gas.
Question 9: What happens if a metal is lower in the reactivity series than hydrogen?
Answer: The metal will not displace hydrogen from the acid and no reaction will occur.
Question 10: What type of reaction is the reaction between a metal and an acid?
Answer: It is a redox (reduction-oxidation) reaction.
Question 11: Why is the liberation of hydrogen gas important in the reaction?
Answer: The liberation of hydrogen gas is an indicator that a chemical reaction has occurred and allows for the detection of the reaction.
How do Metal Carbonates and Metal Hydrogen Carbonates React with Acids?
Question 1: What is the general equation for the reaction between a metal carbonate or metal hydrogen carbonate and an acid?
Answer: Metal carbonate/Metal hydrogen carbonate + Acid → Salt + Carbon dioxide + Water.
Question 2: Can you provide an example equation for the reaction between sodium carbonate and hydrochloric acid?
Answer: Na₂CO₃(s) + 2HCl(aq) → 2NaCl(aq) + H₂O(l) + CO₂(g).
Question 3: What is the product of the reaction between sodium hydrogen carbonate and hydrochloric acid?
Answer: The products are sodium chloride, water, and carbon dioxide.
Question 4: What happens when carbon dioxide gas evolved in the reaction is passed through lime water?
Answer: A white precipitate of calcium carbonate is formed.
Question 5: What is the equation for the formation of calcium hydrogen carbonate from carbon dioxide, water, and calcium carbonate?
Answer: CaCO₃(s) + CO₂(g) + H₂O(l) → Ca(HCO₃)₂(aq).
Question 6: What is formed when carbon dioxide dissolves in water?
Answer: Carbonic acid (H₂CO₃) is formed.
Question 7: What happens when carbonic acid reacts with calcium carbonate?
Answer: Soluble calcium hydrogen carbonate is produced.
Question 8: What occurs when excess carbon dioxide is passed through the reaction mixture?
Answer: Soluble calcium hydrogen carbonate Ca(HCO₃)₂ is formed.
Question 9: What are some examples of different forms of calcium carbonate?
Answer: Limestone, chalk, and marble are different forms of calcium carbonate.
Question 10: What happens to the carbon dioxide produced in the reaction between metal carbonates or metal hydrogen carbonates and acids?
Answer: It is evolved as a gas.
Question 11: Can the reaction between metal carbonates and acids be used to identify the presence of carbonates?
Answer: Yes, the formation of carbon dioxide gas is indicative of the presence of carbonates.
Question 12: Does the reaction between metal carbonates and acids produce an effervescence?
Answer: Yes, the evolution of carbon dioxide gas results in effervescence.
Question 13: Can you provide another example equation for the reaction between a metal hydrogen carbonate and hydrochloric acid?
Answer: NaHCO₃ + HCl(aq) → NaCl(aq) + H₂O(l) + CO₂(g).
Question 14: Is water always a product in the reaction between metal carbonates or hydrogen carbonates and acids?
Answer: Yes, water is always formed as a product.
Question 15: Are there any exceptions to the reaction between metal carbonates and acids?
Answer: Some metal carbonates, like those of group 1 elements (alkali metals), are less reactive and do not react with all acids.
Question 16: What are some examples of metal carbonates?
Answer: Sodium carbonate (Na₂CO₃) and calcium carbonate (CaCO₃).
Question 17: What are some examples of metal hydrogen carbonates?
Answer: Sodium hydrogen carbonate (NaHCO₃), magnesium hydrogen carbonate [ Mg(HCO₃)2], calcium hydrogen carbonate [Ca(HCO₃)₂] are some examples of metal hydrogen carbonate.
Question 18: How can the reaction between metal carbonates and acids be used in practical applications?
Answer: It can be used in the production of carbon dioxide gas, such as in baking or fire extinguishers.
Question 19: Do all metal carbonates and hydrogen carbonates react with acids to produce carbon dioxide?
Answer: Yes, the formation of carbon dioxide is a characteristic reaction of metal carbonates and hydrogen carbonates with acids.
Question 29: Are metal carbonates and hydrogen carbonates strong acids or bases?
Answer: No, they are not strong acids or bases but they are weak bases which react with acids to produce carbon dioxide.
How do Acids and Bases React with each other?
Question 1: What is the equation for the reaction between sodium hydroxide and hydrochloric acid?
Answer: NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l).
Question 2: What type of reaction is the reaction between sodium hydroxide and hydrochloric acid?
Answer: It is a neutralisation reaction.
Question 3: What are the products of a neutralisation reaction?
Answer: The products are salt and water.
Question 4: How can a neutralisation reaction be generally represented?
Answer: Acid + Base → Salt + Water.
Question 5: What happens to the acidic and basic properties of the reactants in a neutralisation reaction?
Answer: They cancel each other out.
Question 6: What is the purpose of neutralisation reactions?
Answer: They are used in various applications, such as preparing salts, regulating pH, and treating acid indigestion.
Question 7: What is the significance of the positive ion and negative ion in the formation of salts?
Answer: The positive ion comes from the acid, and the negative ion comes from the base, combining to form a salt.
Question 8: Are neutralisation reactions exothermic or endothermic?
Answer: Neutralisation reactions are typically exothermic, releasing heat.
Question 9: What are some common sources of acids and bases used in neutralisation reactions?
Answer: Acids can be sourced from substances like vinegar or citrus fruits, while bases can come from substances like sodium hydroxide or baking soda.
Question 10: What is the effect of neutralisation reactions on the pH of a solution?
Answer: Neutralisation reactions tend to bring the pH closer to neutral (pH 7).
Question 11: Are neutralisation reactions reversible?
Answer: Yes, under certain conditions, neutralisation reactions can be reversible.
Question 12: Can neutralisation reactions occur in both aqueous and non-aqueous solutions?
Answer: Yes, neutralisation reactions can occur in both types of solutions.
Question 13: What is the role of water in a neutralisation reaction?
Answer: Water is a product of the reaction and helps dissolve the resulting salt.
Question 14: Do all neutralisation reactions produce water?
Answer: Yes, the formation of water is a characteristic feature of neutralisation reactions.
Question 15: Can a neutralisation reaction occur between a strong acid and a weak base?
Answer: Yes, neutralisation reactions can occur between a strong acid and a weak base.
Question 16: Can you provide an example of a salt formed in a neutralisation reaction?
Answer: Sodium chloride (NaCl) is an example of a salt formed in the neutralisation reaction between sodium hydroxide and hydrochloric acid.
Reaction of Metallic Oxides with Acids
Question 1: What is the product formed when copper oxide reacts with hydrochloric acid?
Answer: Copper(II) chloride is formed.
Question 2: What is the colour of the solution when copper oxide reacts with hydrochloric acid?
Answer: The solution turns blue-green.
Question 3: What is the chemical formula of copper(II) chloride?
Answer: CuCl₂.
Question 4: What is the general equation for the reaction between a metal oxide and an acid?
Answer: Metal oxide + Acid → Salt + Water.
Question 5: Are metal oxides considered acidic or basic oxides?
Answer: Metal oxides are considered basic oxides.
Question 6: What is the role of metal oxides in the reaction with acids?
Answer: Metal oxides act as bases and neutralise the acids.
Question 7: Can you provide an example of a metal oxide reacting with an acid?
Answer: Calcium oxide (CaO) reacting with hydrochloric acid (HCl) to form calcium chloride (CaCl₂) and water (H₂O) is an example.
Question 8: Does the reaction between a metal oxide and an acid release or absorb heat?
Answer: The reaction generally releases heat means it is an exothermic reaction.
Question 9: Can metal oxides react with any type of acid?
Answer: Yes, metal oxides can react with various types of acids.
Question 10: Can you provide another example of a metal oxide reacting with an acid?
Answer: Iron(III) oxide (Fe₂O₃) reacting with sulfuric acid (H₂SO₄) to form iron(III) sulphate [Fe₂(SO₄)3] and water (H₂O) is another example.
Reaction of a Non-metallic Oxide with Base
Question 1: What type of compound is calcium hydroxide?
Answer: Calcium hydroxide is a base.
Question 2: What is the role of carbon dioxide in the reaction?
Answer: Carbon dioxide acts as an acid in the reaction.
Question 3: What is the nature of non-metallic oxides?
Answer: Non-metallic oxides are generally acidic.
Question 4: What are the products formed when non-metallic oxides react with bases?
Answer: The products are salts and water.
Question 5: Can you provide an example of a non-metallic oxide?
Answer: Carbon dioxide (CO₂) is an example of a non-metallic oxide.
Question 6: How is the reactivity of non-metallic oxides different from metallic oxides?
Answer: Metallic oxides tend to exhibit basic properties, while non-metallic oxides exhibit acidic properties.
Question 7: What are the characteristics of an acidic compound?
Answer: An acidic compound can donate hydrogen ions (H⁺) and has a pH value below 7.
Question 8: How do non-metallic oxides contribute to acid rain?
Answer: Non-metallic oxides, such as sulphur dioxide and nitrogen dioxide, combine with water in the atmosphere to form acids, contributing to the acidity of rainwater.
Question 9: Can metallic oxides also react with non-metallic oxides?
Answer: Yes, metallic oxides can react with non-metallic oxides to form salts. Like the reaction between calcium oxide and carbon dioxide.
Question 10: What are some common non-metallic oxides?
Answer: Some common non-metallic oxides include carbon dioxide (CO₂), sulphur dioxide (SO₂), and nitrogen dioxide (NO₂).
Question 11: What is the chemical formula of calcium hydroxide?
Answer: The chemical formula of calcium hydroxide is Ca(OH)₂.
Question 12: What is the pH value of a base?
Answer: The pH value of a base is above 7 upto 14.
Question 13: Can you give the name of salt that formed in the reaction between calcium hydroxide and carbon dioxide?
Answer: Calcium carbonate (CaCO₃) is formed as a salt in the reaction.
Question 14: Why do non-metallic oxides exhibit acidic properties?
Answer: Because non-metallic oxides react with water to form acidic solutions.
Question 15: What is the chemical equation for the reaction between sulphur dioxide and water?
Answer: SO₂(g) + H₂O(l) → H₂SO₃(aq)
Question 16: How do non-metallic oxides affect the environment?
Answer: Non-metallic oxides, such as nitrogen oxides and sulphur oxides, contribute to air pollution and the formation of acid rain.
Question 17: What is the pH value of a neutral solution?
Answer: The pH value of a neutral solution is 7.
What Do All Acids And All Bases Have In Common?
Question 1: What are some common characteristics of acids and bases?
Answer: They both can conduct electricity when dissolved in water and can change the colour of indicators.
Question 2: What property do acids have in terms of releasing ions in water?
Answer: Acids have the ability to release hydrogen ions (H⁺) when dissolved in water.
Question 3: How are acids defined in terms of their ability to donate protons?
Answer: Acids are defined as proton donors, as they can donate hydrogen ions to other substances.
Question 4: What is the characteristic property of bases regarding hydrogen ions?
Answer: Bases can accept hydrogen ions (H⁺) or donate hydroxide ions (OH⁻) when dissolved in water.
Question 5: How are bases defined in terms of their ability to accept protons?
Answer: Bases are defined as proton acceptors, as they can accept hydrogen ions from other substances.
Question 6: What happens when acids and bases react in a neutralisation process?
Answer: There ions combine to form salt and water through a double displacement reaction.
What Happens to an Acid or a Base in a Water Solution?
Question 1: How do acids and bases conduct electricity in water?
Answer: They produce ions in water that allow the flow of electric current.
Question 2: What happens when acids and bases react in terms of their hydrogen ions and hydroxide ions?
Answer: They combine to form water by neutralising each other’s H⁺ ions and OH⁻ ions.
Question 3: Can acids and bases conduct electricity in their pure form?
Answer: No, they can only conduct electricity when dissolved in water.
Question 4: Can acids and bases react with each other in the absence of water?
Answer: No, their reaction requires the presence of water as a medium.
Question 5: Which type of ions are responsible for conducting electricity in acid solutions?
Answer: Hydrogen ions (H⁺) are responsible for conducting electricity in acid solutions.
Question 6: How do acids and bases differ in terms of their ability to release or accept hydrogen ions?
Answer: Acids release hydrogen ions, while bases accept hydrogen ions or donate hydroxide ions.
Question 7: What is the effect of acids and bases on the conductivity of water?
Answer: Both acids and bases can enhance the conductivity of water due to the presence of ions they produce.
Question 8: Can acids and bases react with each other without the presence of water?
Answer: No, the presence of water is necessary for the reaction between acids and bases.
Question 9: Are all acids capable of releasing the same number of hydrogen ions?
Answer: No, the number of hydrogen ions released by acids can vary depending on their concentration and strength.
Question 10: What happens when calcium hydroxide reacts with carbon dioxide?
Answer: Calcium hydroxide reacts with carbon dioxide to form salt and water.
Question 11: How is the reaction between HCl and water represented?
Answer: HCl + H₂O → (H₃O⁺) + Cl-.
Question 12: How are hydrogen ions represented when combined with water molecules?
Answer: Hydrogen ions are represented as H⁺ (aq) or H₃O⁺.
Question 13: What do acids release when dissolved in water?
Answer: Acids release H₃O⁺ or H⁺ (aq) ions.
Question 14: What ions do solid bases generate when dissolved in water?
Answer: Solid bases generate hydroxide (OH⁻) ions.
Question 15: What are soluble bases called?
Answer: Soluble bases are called alkalis.
Question 16: What is the result of the reaction between hydrogen ions (H⁺) and hydroxide ions (OH⁻)?
Answer: The formation of water (H₂O) occurs.
Question 17: Why must caution be taken when mixing concentrated acids with water?
Answer: Caution must be taken to prevent excessive heat generation, splashing, and potential burns.
Question 18: How should acids be added when diluting them?
Answer: Acids should be added slowly to water while stirring constantly.
Question 19: Why is adding water to concentrated acids not recommended?
Answer: Adding water to concentrated acids can cause a rapid release of heat, leading to splashing and container breakage.
Question 20: What caution signs are used for concentrated sulphuric acid and sodium hydroxide pellets?
Answer: Warning signs are used to alert users of potential hazards and about the corrosive nature of the acid.
Question 21: What is the term for the process of decreasing concentration by adding water?
Answer: Dilution.
Question 22: What is the purpose of dilution?
Answer: Dilution allows for safer handling, manipulation, and adjustment of concentration.
How Strong Are Acid Or Base Solutions?
Question 1: What happens when acids or bases are dissolved in water in terms of ion concentration?
Answer: The concentration of ions per unit volume decreases.
Question 2: What type of reaction is the mixing of acids and bases with water?
Answer: It is an exothermic process that releases heat.
Question 3: How are hydrogen ions represented when combined with water molecules?
Answer: Hydrogen ions are represented as H⁺ (aq) or H₃O⁺.
Question 4: What ions do bases generate when dissolved in water?
Answer: Bases generate hydroxide (OH⁻) ions.
Question 5: Why is caution necessary when mixing concentrated acids with water?
Answer: Excessive heat generation and potential hazards can occur.
Question 6: Why are concentrated sulphuric acid and sodium hydroxide pellets labelled with warning signs?
Answer: They are labelled to alert users of potential hazards.
Question 7: How is the reaction between hydrochloric acid and water represented in terms of ions?
Answer: H⁺ (aq) + Cl- (aq) + H₂O → H₃O⁺ (aq) + Cl- (aq).
Question 8: What is the common characteristic of all acids?
Answer: Their ability to release hydrogen ions (H⁺) when dissolved in water.
Question 9: What is the common characteristic of all bases?
Answer: Their ability to accept hydrogen ions (H⁺) or donate hydroxide ions (OH⁻) when dissolved in water.
Importance of pH in Everyday Life
Question 1: What does the pH scale measure?
Answer: Hydrogen ion concentration in a solution.
Question 2: What is the range of the pH scale?
Answer: From 0 to 14.
Question 3: What does a pH value of 7 indicate?
Answer: A neutral solution.
Question 4: How does the hydronium ion concentration relate to the pH value?
Answer: Higher hydronium ion concentration corresponds to lower pH values.
Question 5: What determines the strength of an acid?
Answer: The number of hydrogen ions (H⁺) it produces.
Question 6: What determines the strength of a base?
Answer: The number of hydroxide ions (OH⁻) it produces.
Question 7: How do strong acids compare to weak acids in terms of hydrogen ion production?
Answer: Strong acids produce more hydrogen ions.
Question 8: How do strong bases compare to weak bases in terms of hydroxide ion production?
Answer: Strong bases produce more hydroxide ions.
Question 9: What is the significance of the pH value in relation to acidity or alkalinity?
Answer: Values below 7 indicate acidity, while values above 7 indicate alkalinity.
Question 10: What does a low pH value indicate?
Answer: Higher acidity.
Question 11: What does a high pH value indicate?
Answer: Higher alkalinity.
Question 12: What is the meaning of the term “potenz” in the context of the pH scale?
Answer: It means “power” in German.
Question 13: How does the concentration of hydrogen ions affect the pH value?
Answer: Higher concentration of hydrogen ions leads to a lower pH value.
Question 14: How does the concentration of hydroxide ions relate to the alkalinity of a solution?
Answer: Higher concentrations of hydroxide ions contribute to higher alkalinity.
Question 15: What is the pH of a solution that is neither acidic nor alkaline?
Answer: A pH of 7, indicating a neutral solution.
Question 16: How does the pH of a solution change as it becomes more acidic?
Answer: The pH value decreases.
Question 17: How does the pH of a solution change as it becomes more alkaline?
Answer: The pH value increases.
Question 18: How does the pH value of a solution relate to the concentration of hydrogen ions?
Answer: A lower pH value indicates a higher concentration of hydrogen ions.
pH of Some Substances
Question 1: What is the approximate pH value of saliva before a meal?
Answer: 7-7.5 (Slightly basic).
Question 2: What is the approximate pH value of saliva after a meal?
Answer: 6.5 – 7 (Slightly acidic).
Question 3: What is the pH value of lemon juice?
Answer: 2-3 (Acidic).
Question 4: What is the pH value of a colourless aerated drink?
Answer: 3-4 (Acidic).
Question 5: What is the pH value of carrot juice?
Answer: 5-6 (Acidic).
Question 6: What is the pH value of coffee?
Answer: 5-6 (Acidic).
Question 7: What is the pH value of tomato juice?
Answer: 4-5 (Acidic).
Question 8: What is the pH value of tap water?
Answer: 7 (Neutral).
Question 9: What is the pH value of 1M NaOH?
Answer: 13-14 (Basic).
Question 10: What is the pH value of 1M HCl?
Answer: 0-1 (Acidic).
Question 11: Why is the pH range of 7.0 to 7.8 crucial for our body?
Answer: It is the range in which living organisms can survive.
Question 12: What is the pH range of acid rain?
Answer: Less than 5.6.
Question 13: How can acid rain affect aquatic life?
Answer: It can lower the pH of water and harm the bodies of aquatic organisms.
Question 14: Why is checking soil pH important for plant growth?
Answer: Plants require a specific pH range for healthy growth.
Question 15: What does the stomach produce for food digestion?
Answer: Hydrochloric acid.
Question 16: What can excessive acid production in the stomach cause?
Answer: Pain and irritation during indigestion.
Question 17: What are antacids used for?
Answer: They are used to neutralise excess stomach acid and relieve discomfort.
Question 18: What pH level can lead to tooth decay?
Answer: Below 5.5.
Question 19: How does tooth decay occur?
Answer: When the mouth’s pH drops below 5.5, leading to the corrosion of tooth enamel.
Question 20: How do bacteria in the mouth contribute to tooth decay?
Answer: They produce acids by breaking down sugars and food particles.
Question 21: How can cleaning the mouth after eating help prevent tooth decay?
Answer: It helps remove food particles and reduce acid production.
Question 22: What can basic toothpaste do to protect against tooth decay?
Answer: It can neutralise excess acid and protect tooth enamel.
Question 23: What can be applied to relieve the burning sensation caused by bee stings or nettle leaf stings?
Answer: Baking soda, a mild base.
Question 24: What is the primary acid in vinegar?
Answer: Acetic acid.
Question 25: What acid is most abundant in lemons?
Answer: Citric acid.
Question 26: Which acid is responsible for the tangy flavour of sour milk or curd?
Answer: Lactic acid.
Question 27: What acid contributes to the acidic and citrusy taste of oranges?
Answer: Citric acid.
Question 28: What acid gives tamarind its unique sour taste?
Answer: Tartaric acid.
Question 29: Which acid causes the painful sensation in ant stings?
Answer: Methanoic acid or formic acid.
Question 30: What acid is responsible for the acidic taste of tomatoes?
Answer: Oxalic acid.
Question 31: Which acid is found in nettle stings and causes discomfort?
Answer: Methanoic acid.
Salts
Question 1: What is the general physical state of salts at room temperature?
Answer: Solid.
Question 2: How do salts typically appear in terms of their structure?
Answer: Crystalline.
Question 3: Do salts exhibit conductivity?
Answer: Yes.
Question 4: What are some characteristics of salts?
Answer: Crystalline structure, solid at room temperature, and varying solubility in water.
Question 5: How are salts different from acids and bases?
Answer: They have unique properties and are formed by the combination of an acid and a base.
pH of Salts
Question 1: What is the pH value of a salt formed from a strong acid and a strong base?
Answer: 7 (neutral).
Question 2: Is the solution of a neutral salt acidic or basic?
Answer: Neither. It is neutral.
Question 3: Are salts formed from a strong acid and a weak base considered basic?
Answer: No, they are acidic.
Question 4: What determines the pH value of a salt solution?
Answer: The nature of the acid and base used to form the salt.
Question 5: What is the pH value of a neutral salt solution?
Answer: 7 (neutral).
Question 6: Is the acidity or basicity of a salt solution affected by the strength of the acid or base used?
Answer: Yes, it is influenced by the strength of the acid or base.
Question 7: Can a salt formed from a strong acid and a weak base be acidic?
Answer: Yes, it will be acidic.
Question 8: Can a salt formed from a strong base and a weak acid be basic?
Answer: Yes, it will be basic.
Question 9: What is the pH value of a salt solution formed from a weak acid and a weak base?
Answer: Near to 7.
Question 10: Does the presence of a weak acid in a salt solution make it acidic?
Answer: Yes, it contributes to the acidity.
Question 11: Does the presence of a weak base in a salt solution make it basic?
Answer: Yes, it contributes to the basicity.
Question 12: Can a salt solution have a pH value greater than 7 if it is formed from a weak acid and a strong base?
Answer: Yes, it will still be basic.
Question 13: Can a salt solution have a pH value less than 7 if it is formed from a strong acid and a weak base?
Answer: Yes, it will be acidic.
Chemicals from Common Salt
Question 1: What is sodium chloride commonly known as?
Answer: Common salt.
Question 2: How is sodium chloride formed?
Answer: By the combination of hydrochloric acid and sodium hydroxide.
Question 3: Is sodium chloride considered a neutral salt?
Answer: Yes, it has a pH of 7.
Question 4: What is the main salt present in seawater?
Answer: Sodium chloride.
Question 5: Can sodium chloride be separated from other salts in seawater?
Answer: Yes.
Question 6: What is the name given to solid salt deposits?
Answer: Rock salt.
Question 7: What is the colour of rock salt crystals?
Answer: Brown (due to impurities).
Question 8: How are rock salt deposits obtained?
Answer: Through mining.
Question 9: What is the process of obtaining rock salt similar to?
Answer: Coal mining.
Question 10: What is the common use of sodium chloride?
Answer: It is commonly used in food.
Question 11: How many substances can be produced from common salt?
Answer: Sodium hydroxide, baking soda, washing soda, bleaching powder etc.
Sodium hydroxide
Question 1: What is the process called when sodium chloride decomposes through the passage of electricity?
Answer: The chlor-alkali process.
Question 2: What are the three products formed in the chlor-alkali process?
Answer: Sodium hydroxide, chlorine gas, and hydrogen gas.
Question 3: Where is chlorine gas released in the chlor-alkali process?
Answer: At the anode.
Question 4: Where is hydrogen gas produced in the process?
Answer: At the cathode.
Question 5: What is formed near the cathode in the chlor-alkali process?
Answer: Sodium hydroxide solution.
Question 6: Are all the products obtained from the chlor-alkali process are gases?
Answer: No, sodium hydroxide solution is also obtained which is in aqueous form..
Question 7: Does the chlor-alkali process involve the use of chemicals?
Answer: Yes, sodium chloride and electricity are used in the process.
Question 8: Can the chlorine gas obtained in the sodium hydroxide formation process be used for disinfection purposes?
Answer: Yes, chlorine gas has disinfection applications.
Question 9: Can hydrogen gas obtained in the sodium hydroxide formation process be used as a fuel?
Answer: Yes, hydrogen gas can be used as a fuel source.
Bleaching powder
Question 1: How is chlorine gas obtained for the production of bleaching powder?
Answer: It is obtained from the electrolysis of aqueous sodium chloride.
Question 2: What is bleaching powder created by reacting chlorine with?
Answer: Dry slaked lime (calcium hydroxide).
Question 3: What is the chemical equation for the formation of bleaching powder?
Answer: Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O.
Question 4: What are some applications of bleaching powder?
Answer: Bleaching cotton, linen, wood pulp, washed clothes, serving as an oxidising agent, and purifying drinking water.
Question 5: What is the main ingredient of bleaching powder?
Answer: Chlorine and slaked lime.
Question 6: Does bleaching powder contain chlorine?
Answer: Yes, it contains chlorine.
Question 7: Can bleaching powder be used for household cleaning purposes?
Answer: Yes, it can be used for household cleaning.
Question 8: Is bleaching powder a white-coloured substance?
Answer: Yes, it is usually white in colour.
Question 9: Is chlorine a strong oxidising agent?
Answer: Yes, chlorine is a strong oxidising agent.
Question 10: Does bleaching powder have a strong smell?
Answer: Yes, it has a distinctive odour.
Question 11: Is bleaching powder safe to use?
Answer: It should be handled with caution and used according to instructions.
Question 12: Can bleaching powder disinfect surfaces?
Answer: Yes, it has disinfecting properties.
Question 13: Does bleaching powder react with acids?
Answer: Yes, it reacts with acids to release chlorine gas.
Question 14: What is the purpose of using bleaching powder in the textile industry?
Answer: To bleach cotton and linen fabrics.
Question 15: How does bleaching powder help in purifying drinking water?
Answer: By eliminating germs and bacteria.
Question 16: What is the common name for calcium hypochlorite or Calcium oxychloride?
Answer: Bleaching powder.
Question 17: Is bleaching powder soluble in water?
Answer: Yes, it is soluble in water.
Question 18: Can bleaching powder be used as a disinfectant?
Answer: Yes, it has disinfectant properties.
Question 19: Does bleaching powder react with organic matter?
Answer: Yes, it can react with organic matter.
Question 20: Is the production of bleaching powder an industrial process?
Answer: Yes, it is produced on an industrial scale.
Question 21: Can bleaching powder be used for household stain removal?
Answer: Yes, it can help remove stains from fabrics.
Question 22: Can bleaching powder be used for wood bleaching?
Answer: Yes, it is used in the wood industry for bleaching wood products.
Baking soda
Question 1: What is the chemical formula for baking soda?
Answer: NaHCO₃
Question 2: What is one common use of baking soda in the kitchen?
Answer: Making crispy pakoras and for faster cooking.
Question 3: What raw material is used to produce sodium hydrogen carbonate?
Answer: Sodium chloride, water, carbon dioxide and ammonia.
Question 4: What is the balanced chemical equation for the formation of baking soda?
Answer: NaCl + H₂O + CO₂ + NH₃ → NH₄Cl + NaHCO₃
Question 5: What type of salt is baking soda?
Answer: Basic salt.
Question 6: What does baking soda transform into when heated during cooking?
Answer: Sodium carbonate, water, and carbon dioxide.
Question 7: What is the purpose of baking powder in baking?
Answer: It helps bread or cake rise and become soft and spongy.
Question 8: What is one household use of baking soda?
Answer: It is an ingredient in antacids.
Question 9: What type of fire extinguishers use baking soda?
Answer: Soda-acid fire extinguishers.
Question 10: What role does baking soda play in soda-acid fire extinguishers?
Answer: It helps to suppress fires by releasing carbon dioxide when mixed with acid.
Question 11: What is the purpose of adding a mild edible acid to baking soda?
Answer: It reacts with baking soda to produce carbon dioxide gas, which helps in the rising of baked goods.
Question 12: How does baking soda work as a cleaning agent?
Answer: It has abrasive properties and can help scrub away dirt and grime.
Question 13: What happens when baking soda reacts with an acid?
Answer: It produces carbon dioxide gas, water, and salt.
Question 14: Can baking soda be used as a deodorant?
Answer: Yes, it can help neutralise odours when applied to the underarms.
Question 15: Does baking soda have any medicinal uses?
Answer: It can be used as a home remedy for relieving heartburn or indigestion.
Question 16: What is the pH of baking soda?
Answer: Baking soda is alkaline and has a pH of around 8-9.
Question 17: Can baking soda be used to clean silverware?
Answer: Yes, it can help remove tarnish from silverware when used in a cleaning solution.
Washing soda
Question 1: What is another name for sodium carbonate?
Answer: Washing soda.
Question 2: How is washing soda obtained from baking soda?
Answer: By heating baking soda and recrystallizing sodium carbonate.
Question 3: Is washing soda acidic or basic?
Answer: Washing soda is basic.
Question 4: Does the presence of water molecules make Na₂CO₃ wet?
Answer: No, water molecules are chemically bound within the crystal structure.
Question 5: Which industries use washing soda?
Answer: Glass, soap, and paper manufacturing industries.
Question 6: What can sodium carbonate be used for in households?
Answer: It can be used as a cleaning agent.
Question 7: What is the chemical formula for sodium carbonate?
Answer: Na₂CO₃.
Question 8: What does the formula Na₂CO₃.10H₂O indicate about washing soda?
Answer: It indicates that washing soda contains ten water molecules.
Question 9: Can washing soda be used as a cleaning agent in households?
Answer: Yes, it can be used for household cleaning purposes.
Question 10: How is washing soda effective in removing permanent hardness from water?
Answer: It reacts with the ions causing hardness and forms insoluble precipitates.
Question 11: Can washing soda be used as a laundry detergent?
Answer: Yes, it can be used as a laundry booster or to remove stains.
Question 12: Does washing soda have any applications in the production of other chemicals?
Answer: Yes, it is used in the production of other sodium compounds like borax having molecular formula of Na₂[B₄O₅(OH)₄]·8H₂O.
Question 13: Is washing soda safe to use in household cleaning?
Answer: Washing soda should be handled with care and used according to the recommended guidelines for safety.
Are The Crystals Of Salts Really Dry?
Question 1: What gives copper sulphate crystals their blue colour?
Answer: Water of crystallisation.
Question 2: What happens when copper sulphate crystals are heated?
Answer: The crystals turn white as the water of crystallisation is removed.
Question 3: How does the blue colour reappear in copper sulphate crystals?
Answer: When the white crystals are moistened with water.
Question 4: What is water of crystallisation?
Answer: It refers to a fixed number of water molecules present in one formula unit of a salt.
Question 5: What is the chemical formula of copper sulphate?
Answer: CuSO₄.5H₂O.
Question 6: What is another salt that contains water of crystallisation?
Answer: Gypsum.
Question 7: How many water molecules are present in the formula unit of gypsum?
Answer: Two water molecules.
Question 8: How does the removal of water of crystallisation affect the colour of copper sulphate crystals?
Answer: It causes the crystals to turn white.
Question 9: How does adding water to white copper sulphate crystals affect their colour?
Answer: The blue colour reappears.
Question 10: Can copper sulphate crystals lose their blue colour after the removal of water of crystallisation?
Answer: Yes
Question 11: What is the role of water of crystallisation in copper sulphate crystals?
Answer: It gives them their blue colour and helps maintain their crystal structure.
Question 12: How does the presence of water of crystallisation affect the chemical formula of a salt?
Answer: It is included in the formula as a separate component.
Question 13: Can the water of crystallisation be easily separated from copper sulphate crystals?
Answer: Yes, by heating the crystals.
Question 14: Is gypsum a white or blue crystal?
Answer: Gypsum is a white crystal.
Question 15: Does gypsum turn blue when moistened with water?
Answer: No, gypsum does not exhibit a colour change when moistened.
Question 16: How does the chemical formula of gypsum differ from copper sulphate?
Answer: Gypsum has a formula of CaSO₄.2H₂O, while copper sulphate has a formula of CuSO₄.5H₂O.
Plaster of Paris
Question 1: What is formed when gypsum is heated at 373 K?
Answer: Calcium sulphate hemihydrate.
Question 2: What is another name for calcium sulphate hemihydrate?
Answer: Plaster of Paris.
Question 3: How is Plaster of Paris used in the medical field?
Answer: It is used as a plaster to support fractured bones.
Question 4: What happens when Plaster of Paris is mixed with water?
Answer: It reverts back to gypsum and forms a hard solid mass.
Question 5: What is the chemical equation for the reaction between Plaster of Paris and water?
Answer: CaSO₄.1/2H₂O + 3/2 H₂O → CaSO₄.2H₂O.
Question 6: What does the notation “1/2H₂O” represent in the chemical formula of Plaster of Paris?
Answer: It signifies that half a water molecule is attached as water of crystallisation.
Question 7: How many formula units of CaSO₄ share one molecule of water in Plaster of Paris?
Answer: Two formula units.
Question 8: Besides medical applications, where else is Plaster of Paris used?
Answer: It is used in making toys, decorative materials, and achieving smooth surfaces.
Question 9: What is the appearance of Plaster of Paris?
Answer: It is a white powder.
Question 10: What is the colour of copper sulphate crystals due to?
Answer: The presence of water of crystallisation.
Question 11: What happens to copper sulphate crystals when they are heated?
Answer: The water of crystallisation is removed, and the crystals turn white.
Question 12: What causes the blue colour to reappear in copper sulphate crystals?
Answer: Moistening the white crystals with water.
Question 13: How many water molecules are present in the formula unit of copper sulphate?
Answer: Five water molecules.
Question 14: Does the presence of water of crystallisation mean that the molecule is wet?
Answer: No, it indicates that water is chemically bound within the crystal structure.
Question 15: What is the chemical formula of gypsum?
Answer: CaSO₄.2H₂O.
Question 16: What happens to gypsum when it is heated?
Answer: It loses water molecules and transforms into calcium sulphate hemihydrate.
Question 17: What is the common name for calcium sulphate hemihydrate?
Answer: Plaster of Paris.